So, here's a prediction.
If we get our cities right,
we just might survive the 21st century.
We get them wrong,
and we're done for.

Cities are the most extraordinary
experiment in social engineering
that we humans have ever come up with.
If you live in a city,
and even if you live in a slum —
which 20 percent of the world's
urban population does —
you're likely to be healthier,
wealthier, better educated
and live longer than your country cousins.
There's a reason why three million people
are moving to cities
every single week.
Cities are where the future happens first.
They're open, they're creative,
they're dynamic, they're democratic,
they're cosmopolitan,
they're sexy.
They're the perfect antidote
to reactionary nationalism.
But cities have a dark side.
They take up just three percent
of the world's surface area,
but they account for more than 75 percent
of our energy consumption,
and they emit 80 percent
of our greenhouse gases.
There are hundreds of thousands
of people who die in our cities
every single year from violence,
and millions more who are killed
as a result of car accidents
and pollution.
In Brazil, where I live,
we've got 25 of the 50 most homicidal
cities on the planet.
And a quarter of our cities
have chronic water shortages —
and this, in a country with 20 percent
of the known water reserves.

So cities are dual-edged.
Part of the problem is that,
apart from a handful of megacities
in the West and the Far East,
we don't know that much
about the thousands of cities
in Africa, in Latin America, in Asia,
where 90 percent of all future
population growth is set to take place.
So why this knowledge gap?
Well, part of the problem
is that we still see the world
through the lens of nation-states.
We're still locked
in a 17th-century paradigm
of parochial national sovereignty.
And yet, in the 1600's,
when nation-states were really
coming into their own,
less than one percent
of the world's population
resided in a city.
Today, it's 54 percent.
And by 2050, it will be
closer to 70 percent.
So the world has changed.
We have these 193 nation-states,
but we have easily as many cities
that are beginning to rival them
in power and influence.

Just look at New York.
The Big Apple has 8.5 million people
and an annual budget
of 80 billion dollars.
Its GDP is 1.5 trillion,
which puts it higher
than Argentina and Australia,
Nigeria and South Africa.
Its roughly 40,000 police officers
means it has one of the largest
police departments in the world,
rivaling all but
the largest nation-states.
But cities like New York
or São Paulo
or Johannesburg
or Dhaka
or Shanghai —
they're punching above
their weight economically,
but below their weight politically.
And that's going to have to change.
Cities are going to have to find
their political voice
if we want to change things.

Now, I want to talk to you
a little bit about the risks
that cities are facing —
some of the big mega-risks.
I'm also going to talk to you briefly
about some of the solutions.
I'm going to do this
using a big data visualization
that was developed with Carnegie Mellon's
CREATE Lab and my institute,
along with many, many others.
I want you to first imagine the world
not as made up of nation-states,
but as made up of cities.
What you see here is every single city
with a population
of a quarter million people or more.
Now, without going into technical detail,
the redder the circle,
the more fragile that city is,
and the bluer the circle,
the more resilient.
Fragility occurs when
the social contract comes unstuck.
And what we tend to see is a convergence
of multiple kinds of risks:
income inequality,
poverty,
youth unemployment,
different issues around violence,
even exposure to droughts,
cyclones and earthquakes.
Now obviously, some cities
are more fragile than others.

The good news, if there is any,
is that fragility is not
a permanent condition.
Some cities that were once the most
fragile cities in the world,
like Bogotá in Colombia
or Ciudad Juárez in Mexico,
have now fallen more
around the national average.
The bad news is
that fragility is deepening,
especially in those parts of the world
that are most vulnerable,
in North Africa, the Middle East,
in South Asia and Central Asia.
There, we're seeing fragility rising
way beyond scales we've ever seen before.
When cities become too fragile
they can collapse,
tip over and fail.
And when that happens,
we have explosive forms of migration:
refugees.

There are more than 22 million
refugees in the world today,
more than at any other time
since the second world war.
Now, there's not one refugee crisis;
there are multiple refugee crises.
And contrary to what
you might read in the news,
the vast majority of refugees
aren't fleeing from poor countries
to wealthy countries,
they're moving from poor cities
into even poorer cities —
often, cities nearby.
Every single dot on this map
represents an agonizing story
of struggle and survival.
But I want to briefly tell you
about what's not on that map,
and that's internal displacement.
There are more than 36 million people
who have been internally displaced
around the world.
These are people living
in refugee-like conditions,
but lacking the equivalent international
protection and assistance.
And to understand their plight,
I want to zoom in briefly on Syria.

Syria suffered one of the worst droughts
in its history between 2007 and 2010.
More than 75 percent of its agriculture
and 85 percent of its livestock
were wiped out.
And in the process,
over a million people moved into cities
like Aleppo, Damascus and Homs.
As food prices began to rise,
you also had equivalent levels
of social unrest.
And when the regime of President Assad
began cracking down,
you had an explosion of refugees.
You also had over six million
internally displaced people,
many of whom when on to become refugees.
And they didn't just move
to neighboring countries like Jordan
or Lebanon or Turkey.
They also moved up north
towards Western Europe.
See, over 1.4 million Syrians
made the perilous journey
through the Mediterranean
and up through Turkey
to find their way
into two countries, primarily:
Germany and Sweden.

Now, climate change —
not just drought, but also sea level rise,
is probably one of the most severe
existential threats
that cities face.
That's because two-thirds
of the world's cities are coastal.
Over 1.5 billion people live in low-lying,
flood-prone coastal areas.
What you see here is a map
that shows sea level rise
in relation to changes in temperature.
Climate scientists predict
that we're going to see
anywhere between three
and 30 feet of sea level rise
this side of the century.
And it's not just low island nation-states
that are going to suffer —
Kiribati or the Maldives
or the Solomons or Sri Lanka —
and they will suffer,
but also massive cities like Dhaka,
like Hong Kong,
like Shanghai.
Cities of 10, 20, 30 million
people or more
are literally going to be wiped off
the face of this earth.
They're going to have to adapt,
or they're going to die.

I want to take you also
all the way over to the West,
because this isn't just a problem
in Asia or Africa or Latin America,
this is a problem also in the West.
This is Miami.
Many of you know Miami
is one of the wealthiest cities
in the United States;
it's also one of the most flood-prone.
That's been made painfully evident
by natural disasters throughout 2017.
But Miami is built
on porous limestone — a swamp.
There's no way any kind of flood barrier
is going to keep
the water from seeping in.
As we scroll back,
and we look across the Caribbean
and along the Gulf,
we begin to realize
that those cities that have suffered
worst from natural crises —
Port-au-Prince, New Orleans, Houston —
as severe and as awful
as those situations have been,
they're a dress rehearsal
for what's to come.

No city is an island.
Every city is connected
to its rural hinterland
in complex ways —
often, in relation
to the production of food.
I want to take you to the northern part
of the Amazon, in Rondônia.
This is one of the world's largest
terrestrial carbon sinks,
processing millions of carbon
every single year.
What you see here is a single road
over a 30-year period.
On either side you see land being
cleared for pasture, for cattle,
but also for soy and sugar production.
You're seeing deforestation
on a massive scale.
The red area here implies a net loss
of forest over the last 14 years.
The blue, if you could see it —
there's not much —
implies there's been an incremental gain.
Now, as grim and gloomy
as the situation is — and it is —
there is a little bit of hope.

See, the Brazilian government,
from the national to the state
to the municipal level,
has also introduced a whole range —
a lattice — of parks and protected areas.
And while not perfect,
and not always limiting encroachment,
they have served
to tamp back deforestation.
The same applies not just in Brazil
but all across the Americas,
into the United States, Canada
and around the world.
So let's talk about solutions.
Despite climate denial
at the highest levels,
cities are taking action.
You know, when the US pulled out
of the Paris Climate Agreement,
hundreds of cities in the United States
and thousands more around the world
doubled down on their climate commitments.

(Applause)

And when the White House cracked down
on so-called "undocumented migrants"
in sanctuary cities,
hundreds of cities and counties
and states sat up in defiance
and refused to enact that order.

(Applause)

So cities are and can take action.

But we're going to need
to see a lot more of it,
especially in the global south.
You see, parts of Africa
and Latin America are urbanizing
before they industrialize.
They're growing at three times
the global average
in terms their population.
And this is putting enormous strain
on infrastructure and services.
Now, there is a golden opportunity.
It's a small opportunity but a golden one:
in the next 10 to 20 years,
to really start designing in
principles of resilience into our cities.
There's not one single way of doing this,
but there are a number of ways
that are emerging.
And I've spoken with hundreds
of urban planners,
development specialists,
architects and civic activists,
and a number of recurring
principles keep coming out.
I just want to pass on six.

First: cities need a plan
and a strategy to implement it.
I mean, it sounds crazy,
but the vast majority of world cities
don't actually have a plan
or a vision.
They're too busy putting out daily fires
to think ahead strategically.
I mean, every city wants to be creative,
happy, liveable, resilient —
who doesn't?
The challenge is, how do you get there?
And urban governance plays a key role.
You could do worse than take a page
from the book of Singapore.
In 1971, Singapore set
a 50-year urban strategy
and renews it every five years.
What Singapore teaches us
is not just the importance of continuity,
but also the critical role
of autonomy and discretion.
Cities need the power
to be able to issue debt,
to raise taxes,
to zone effectively,
to build affordable housing.
What cities need is nothing less
than a devolution revolution,
and this is going to require
renegotiating the terms of the contract
with a nation-state.

Second:
you've got to go green.
Cities are already leading
global decarbonization efforts.
They're investing in congestion
pricing schemes,
in climate reduction emission targets,
in biodiversity, in parks
and bikeways and walkways
and everything in between.
There's an extraordinary menu of options
they have to choose from.
One of the great things is,
cities are already investing heavily
in renewables — in solar and wind —
not just in North America, but especially
in Western Europe and parts of Asia.
There are more than 8,000 cities
right now in the world today
with solar plants.
There are 300 cities that have declared
complete energy autonomy.
One of my favorite stories
comes from Medellín,
which invested in a municipal
hydroelectric plant,
which doesn't only service
its local needs,
but allows the city to sell excess energy
back onto the national grid.
And it's not alone.
There are a thousand
other cities just like it.

Third: invest in integrated
and multi-use solutions.
The most successful cities are those
that are going to invest in solutions
that don't solve just one problem,
but that solve multiple problems.
Take the case of integrated
public transport.
When done well —
rapid bus transit,
light rail,
bikeways, walkways, boatways —
these can dramatically reduce
emissions and congestion.
But they can do a lot more than that.
They can improve public health.
They can reduce dispersion.
They can even increase safety.
A great example of this comes from Seoul.
You see, Seoul's population doubled
over the last 30 years,
but the footprint barely changed.
How?
Well, 75 percent
of Seoul's residents get to work
using what's been described as
one of the most extraordinary
public transport systems
in the world.
And Seoul used to be car country.

Next, fourth:
build densely but also sustainably.
The death of all cities is the sprawl.
Cities need to know
how to build resiliently,
but also in a way that's inclusive.
This is a picture right here
of Dallas-Fort Worth.
And what you see is its population
also doubled over the last 30 years.
But as you can see, it spread
into edge cities and suburbia
as far as the eye can see.
Cities need to know when not to build,
so as not to reproduce urban sprawl
and slums of downward accountability.
The problem with Dallas-Forth Worth is
just five percent of its residents get
to work using public transport — five.
Ninety-five percent use cars,
which partly explains why it's got
some of the longest commuting times
in North America.
Singapore, by contrast, got it right.
They built vertically
and built in affordable housing to boot.

Fifth: steal.
The smartest cities are nicking,
pilfering, stealing,
left, right and center.
They don't have time to waste.
They need tomorrow's technology today,
and they're going
to leapfrog to get there.
This is New York,
but it's not just New York
that's doing a lot of stealing,
it's Singapore, it's Seoul, it's Medellín.
The urban renaissance
is only going to be enabled
when cities start borrowing
from one another.

And finally: work in global coalitions.
You know, there are more than 200
inner-city coalitions in the world today.
There are more city coalitions
than there are coalitions
for nation-states.
Just take a look at the Global
Parliament of Mayors,
set up by the late Ben Barber,
who was driving an urban rights movement.
Or consider the C40,
a marvelous network of cities
that has gathered thousands together
to deliver clean energy.
Or look at the World Economic Forum,
which is developing smart city protocols.
Or the 100 Resilient Cities initiative,
which is leading a resilience revival.
ICLEI, UCLG, Metropolis —
these are the movements of the future.
What they all realize
is that when cities work together,
they can amplify their voice,
not just on the national stage,
but on the global stage.
And with a voice comes,
potentially, a vote —
and then maybe even a veto.

When nation-states default
on their national sovereignty,
cities have to step up.
They can't wait.
And they don't need to ask for permission.
They can exert their own sovereignty.
They understand
that the local and the global
have really, truly come together,
that we live in a global, local world,
and we need to adjust
our politics accordingly.
As I travel around the world
and meet mayors and civic leaders,
I'm amazed by the energy,
enthusiasm and effectiveness
they bring to their work.
They're pragmatists.
They're problem-solvers.
They're para-diplomats.
And in this moment of extraordinary
international uncertainty,
when our multilateral
institutions are paralyzed
and our nation-states are in retreat,
cities and their leaders are our new
21st-century visionaries.
They deserve — no, they have
a right to — a seat at the table.